Spray gun for coating the interior of conduits



Feb. 15, 1949. J, c, CARNEVALE' 2,461,517

SPRAY GUN FOR COATING THE INTERIOR OF CONDUITS Filed Jan. 5, 1945 2Sheefs-Sheef 1 Feb. 15, 1949. J, a, CARNEVALE 2,461,517

SPRAY 01m FOR comma 'm'E IX'I'ERIOR or coununs Filed Jan. 5. 1945 2Sheets-Sheet 2 5 52 V 1r re Patented Feb. 15, 1949 SPRAY GUN FOR COATINGTHE INTERIOR -or CONDUITS John C. Carnevale, Menlo Park, Calif.

Application January 5, 1945, Serial No. 571,487

4 Claims. (CI. 91-44) (Granted under the act of March 3, 1883, as

piping for conveying salt water to the various,

parts of the ship for fire control and other purposes. The piping andconduits which are employed in such systems are internally coated withprotective compositions to prevent undue corrosion from the sea water.Heretofore, the coating has been applied by removing the pipes andconduits, section by section, from the ship and submerging each sectionin a bath of the coating composition, removing it, hanging it up todrain, allowing it to dry, and then reinstalling it in the ship. Thereare disadvantages incident to such procedure, namely, the necessity, oftying up the ship for a considerable period, of removing all the pipingand valves connected thereto which involves considerable labor and time,a waste of amended April 30, 1928; 370 O. G. 75?) 'their opposite ends,means for connecting said the coating composition and damage to thecoated surfaceof the conduit during reinstallation.

It is an object of this invention to provide means with which the insidesurface of hollow bodies, specifically piping and conduits, may becoated with a protective composition in situ, which will be effective instraight or angular piping, which will be inexpensive and easy tooperate.

As illustrated herein, invention resides in means movable lengthwise ofa hollow member adapted to emit a diffused cloud of a coating materialfrom substantially a point source, substantially at the longitudinalaxis of the hollow member, radially outward, and supporting means forautomatically maintaining the aforesaid means concomitant with thelongitudinal axis of the hollow member. More specifically, in one formthe aforesaid means comprise an articulated body having a nozzleattached to one ,end and a supply conduit attached to the opposite end,the articulated sections of the body having attached thereto, radiallydisposed adjustable arms adapted to support the articulated body inconcentric relation with respect to the hollow body, and anti-frictionrollers at the ends of the arms adapted to engage the inside surface ofthe hollow body, and thereby to facilitate movement of the devicelongitudinally. In another form of the invention, there is associatedwith the first menelongated members to said first named means, meansadjustable longitudinally of the hollow body to expand the connectingmeans-radially, and yieldable means opposing the expansion'of saidconnecting means.

The invention will now be described in detail with reference to theaccompanying, drawings,

in which:

Fig. 1 is av plan view of the spray coating device which forms thesubject matter of thepresent invention; i I

Fig. 2 is a perspective view of the spray coating device as seen lookingat the nozzle end thereof;

Fig.- 3 is a front view looking directly at the nozzle; I

Fig. 4 is a plan view showing the articulated parts thereof at an anglewith respect to each other as would be the case when the device wasforced around a bend in the conduit being coated;

Fig. 5 is a longitudinal section through a modified form of the spraycoating device;

Fig. 6 shows a section on the line 6-6 of Fig. 5 looking from the nozzlerearwardly and illustrating the position of the device inside of aconduit C; and

Fig. '7 is a modified form of the invention shown in Fig. 5 in whicheach conduit contacting shoe is provided at its opposite ends withantifriction devices.

Referring to the drawing, the spray coating device for coating theinside .of conduits and piping is represented generally by the referencecharacter 10 and consists of a spray nozzle f2, adapted to eject adiffused cloud of coating composition radially outward and which issupported centrally of a conduit C such as that shown in Fig. 3byradially disposed arms Hi and I6 arranged as will be relatedhereinafter. The nozzle 12, which is of standard construction andadjustable to give a suitable spray of coating material. is threadedonto one end of a hollow body 18 and to the opposite end of this hollowbody is threaded a hollow handle 20 through which air and the coatingcompositionare introduced to the hollow body I8 and the nozzle |2. Thehollow handle 20 has at its free end a threaded portion over whichmay beclamped a flexible supply conduit (not shown) for' conducting thecoating composition from high pressure supply receptacles. A pair ofdiscs 22 and 24 are mounted on the body is, preferably threaded videdwith a slot 82. Through these slots are,

passed screws 84 and 88, respectively, the screws being threaded intothe discs 22 and 24 and serving to hold the arms l4 and i8 rigidlyclamped against one face of the disc. By slacking off on the screws 84and 88, the arms may be adjusted inwardly r outwardly relative to thediscs to provide for adjusting the spray coating device so that it has afreely sliding fit in the conduit to be coated. Each of the arms l4 hasat its terminal end a forwardly projecting portion 88- reception ofdiscs 44 which are journaled therein. The discs 48 and 44 at the ends ofthe respectlve arms are adapted to bear against the inside surface ofthe conduit to which a coating is to be applied, and to facilitatemovement of the spray coating device through the conduit. In

order to reduce the frictional contact between the discs and the wall ofthe conduit and thereby to increase mobility of the spray coating deviceas much as possible, the discs 48 and 44 are provided with a sharpperipheral edge which affords substantially line contact between themand the inner surface of the conduit. The adjustment of each arm 14 islimited only by the length of the slot 88. The adjustment of the arms i8inwardly, however, is limited by the periphery of the disc 24 since theforwardly and rearwardly projecting portion 42 will engage the peripheryof the disc 24 when the arms 18 are moved inwardly. To permit the arm l8to be adjusted inwardly to the same extent as the arms i'4, slots ornotches 48 are formed in the disc 24 oi such width as to accommodate theportion 42. It may also be necessary to notch the portion 42 at 48 itthe portion 42 is not of uniform thickness throughout. In order that thespray coating device may be useful not only in straight conduits, butalso in conduits having bends therein, the body ill of the spray coatingdevice is articulated, the articulation being provided for by a ball 88and socket 52. This arrangement permits substantially universal movementbetween the fore part of the coating device which carries the nozzle l2and'the rear part of the device which includes the handle 28. Slots 84are formed in the socket 82 to accommodate the character 88, comprises anozzle 88 threaded on-. to one end of a hollow body 82 to thempposltethepins 18 and I8 are journaled arms 18, which extend inwardly toward eachother and are pivoted on the opposite ends oi pins Ti and 18 fixedtransversely in posts 18, the latter being formed integral with shoes 88having substantially convex surfaces adapteli, as shown in Fig. 6, tobear against the inner surface of a conduit C. The

. changed to accommodate whatever diameter of shoes 88 being equidistantfrom each other form a three point support for the spray device withinthe conduit, and hence, hold it centrally thereof. Between the legs 88and the sleeve 88 there is disposed a washer 82 and a spring 84, thelatter bearing at one end against the lugs 88 and at its opposite endagainst the washer 82, by its force opposing movement of the sleeve 88toward the lugs 88. The sleeve 88 is provided with an enlarged knurledhead 88, by which the sleeve may be rotated to move it longitudinally onthe body 82 toward or away from the lugs 88, thereby to expand orcontract the shoes 88 with respect to the body 82. It is evident that bythis construction the radial position of the shoes may be conduits istobe coated. While the aforesaid shoes '88 are provided with smoothconvex surfaces which permits the device to slide through the conduit C,if the conduit is of considerable length, it is desirable to reduce thefriction between the device and the inner surfaces of the conduit andthis may be done as illustrated in Fig. 7 by bifurcating the oppositeends of the shoes and journaling discs 88 therein, similar tothe disc 48described in the form of the invention shown in Fig. l.

Preparatory to using the device shown in either of its forms, theoperator adjusts the radial arms i4 and I8 or the sleeve 88 so that therollers 48 and 44 or the shoes 88 freely fit the inside diameter of theconduit which is to be coated. The supply line is then connected to thehandle 28 or to the nipple 84, and the coating material together withair for forcing it through the nozzle is permitted to enter the device.The character of the spray coating material which is to be applied tothe inside surface of the conduit, will be determined by adjustment ofthe spray nozzle i2 in the usual manher, and since such adjustment of anozzle is common in practice, it will not be described herein. Thedevice is then pushed through the conduit slowly and the coatingmaterial will be applied evenly and uniformly over the entire innersurface of the conduit by reason of the fact that the rollers 48 and 44or the shoes 88 hold the spray nozzle i2 centrally of the conduit. Wherethe conduit has bends in it, it is necessary to use the form of theinvention shown in Fig. 1, and also where the conduit is of greatlength. In short straight conduits, the form of the invention shown inFig. 5 may satisfactorily be employed, however, if this is to be usedfor great lengths of conduit its movement through the end of'whi'eh isthreaded a nipple 84 adapted to be connected to a flexible conduit (notshown) for conducting the coating material and air to the nozzle. Formedintegral with the body 82 adiacentto the nozzle 88 are three radiallydisposed lugs 88. At the opposite'end near the nip pie 84 there is asleeve 88 threaded on the body 82, the sleeve having telescopicallydisposed thereon, a collar 18. The lugs 88 and the collar 18 areprovided with hearing posts I2 and 14 having extending therethrough fromopposite sides. pins I2 and 78. on the opposite ends of conduit maygreatly be facilitated by use of the discs 88, as shown in Fig. 7. It isevident that by Using the device described in its various forms, thecoating may be carried out without removing the piping from the ships.and hence the coating operation may be performed without dismantling'the entire piping system and at a minimum loss in time.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royaltiesv thereon or therefor.

What is claimed is:

l. A device for coating the inside surface of an elongated hollowmember, comprising means movable-lengthwise of the hollow member adaptedto emit a diflused spray of coating composition from a substantiallypoint source, substan-' 2. A device for coating the inside surface ofanelongated hollow member, comprising means movable lengthwise of thehollow member adapted to emit a diffused spray of coating compositionfrom a substantially point source, substantially at the longitudinalaxis of the hollow member radially outward, a two part articulatedsupport, one part of which is universally movable with respect to theother, radial arms extending from each part, and anti-friction discs atthe ends of said arms.

3. A device for coating the inside surface of an elongated hollowmember, comprising means movable lengthwise of the hollow member adaptedto emit a diffused spray of coating composition from a substantiallypoint source, substantially at the longitudinal axis of the hollowmember, radially outward, a two part articulated support, the parts ofwhich are universally movable relative toeach other. radially disposedarms extending from each part, the radial arms of anon-s17.

one part terminating in single point wall oon-' tacting means and theradial arms of the other part terminating in two point walls contacting7 means.

4. A device for coating the inside surface of an elongated hollowmember, comprising means movable lengthwise of the hollow member adaptedto emit a diffused spray of coating composition from a substantiallypoint source, substantially at the longitudinal axis of the hollowmember, radially outward, said means comprising a, length of pipe,aspray nozzle fixed to one end thereof,'a

I conduit fixed to the other end thereof, said length of pipe beingarticulated between its ends to pro:

vide elements universally movable with respect to each other, a circularplate threaded onto each element of the pipe, aplurality of arms, meansfor adjustably fastening each arm to the circular plate for movementwith respect thereto in a direction substantially normal to a radialline ex- The following references are of record in the file of thispatent:

UNITED STATES PATENTS Number Name Date 1,942,876 Perkins Jan. 9, 19341,951,221 Tate ....'i Mar. 13, 1934 2,017,042 Dougherty Oct. 15, 19352,348,714 De Flore May 16, 1944 2,353,951

Wood July 18, 1944

